• Title/Summary/Keyword: Mesh Size

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A study on the mesh selectivity of hairtail (Trichiurus lepturus) caught by coastal drift gill net (연안 유자망에 의한 갈치(Trichiurus lepturus)의 망목 선택성에 관한 연구)

  • KIM, Seonghun;KIM, Pyungkwan;JEONG, Seong-Jae;LEE, Kyounghoon;OH, Wooseok
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.55 no.4
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    • pp.285-293
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    • 2019
  • The mesh selectivity of hairtail (Trichiurus lepturus) caught by coastal drift gill net was examined in field experiments with three different mesh sizes (45, 50 and 55 mm) from October to November, 2013 in the coastal areas of south-west of Jeju province. The mesh selectivity tests were conducted with the experimental net to be set middle part of conventional driftnets. The mesh selectivity tests were carried out the total of four times. The selectivity curve was estimated by the Kitahara's and Fujimori's method. In the results, the catch number of hairtail was 653 (125.8 kg) and occupied 34.8% in total catches weight. The optimal mesh size for 50% selection on the minimum landing size (180 mm, AL) and the first maturity size (260 mm, AL) of hairtail were estimated as 47.2 mm and 64.5 mm by master selectivity curves, respectively.

Effect of Fluid Mesh Modeling on Surface Ship Shock Response under Underwater Explosion

  • Lee, Sang-Gab;Kwon, Jeong-Il;Chung, Jung-Hoon
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.04a
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    • pp.351-358
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    • 2001
  • In this study, for the investigation of effects of several parameters, such as fluid mesh boundary size, cylinder or block shape, dimensions of depth, breadth and length at free suface, and fluid mesh element size to the depth direction on a reliable shock response of finite element model under underwater explosion with consideration of the bulk cavitation analysis of a simplified surface ship was carried out using the LS-DYNA3D/USA code. The shock responses were not much affected by the fluid mesh parameters. The computational time was greatly dependent on the number of DAA boundary segments. It is desirable to reduce the DAA boundary segments in the fluid mesh model, and it is not necessary to cover the fluid mesh boundary to or beyond the bulk cavitation zone just for the concerns about an initial shock wave response. It is also the better way to prefer cylinder type of the fluid mesh model to the block one.

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Mesh size and Water Velocity for The growth of Filamentous Periphytic Algae (수질 정화를 위한 부착조류의 성장에 적합한 매질과 유속)

  • Park, Ku-Sung;Kim, Ho-Sub;Choi, Kwang-Hyun;Yoon, Chun-Gyeong;Hwang, Soon-Jin;Gong, Dong-Soo
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2001.10a
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    • pp.435-440
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    • 2001
  • The purpose of this study was to evaluate mesh size and water velocity for the growth of filamentous periphytic algae(FPA). The growth experiment was carried out in the constructed pilot waterway system with nutrient-rich treated wastewater. Growth rate of FPA was highest at water velocity about 10 cm/s. The maximum standing crop of FPA was $253\;{\mu}g\;chl.a/cm^{3}$, and an average of the net productivity was $3.92\;mgDW/cm^{2}/day\;or\;25.3\;{\mu}g\;chl.a/cm^{2}/day$. Biomass development and growth rates of FPA were highest at the net with 20mm mesh size during the fall season and 10mm mesh size during the winter season.

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Tracer diffusion in a polymer network: influence of network flexibility

  • Kim, Haein;Kim, Jun Soo
    • Proceeding of EDISON Challenge
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    • 2017.03a
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    • pp.39-45
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    • 2017
  • We present a Brownian dynamics simulation study on the diffusion of a neutral tracer particle confined in a regularly crosslinked polymer network, especially, when the tracer size is comparable to the mesh size of the network. Polymer networks with different mesh sizes are prepared and compressed to the extent that the total polymer densities become the same. Irrespective of the network mesh size, the tracer diffusion in the networks is slowed down, showing the subdiffusion on intermediate time scales followed by the normal diffusion at long times. However, the confinement effect on the tracer diffusion becomes more significant when network strands are tightly stretched with smaller mesh size. The time scales of dynamic transitions are analyzed in terms of the probability distribution of time-correlated particle displacements.

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Effect of Particle Size and Mixing Ratio on Quality of Fluidized Coated Vitamin C (입자크기와 혼합비에 따른 유동층 코팅 비타민 C의 품질 특성)

  • Park, Su-Jung;Hwang, Sung-Hee;Chung, Hun-Sik;Youn, Kwang-Sup
    • Food Science and Preservation
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    • v.14 no.4
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    • pp.364-368
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    • 2007
  • The purpose of this study was to improve the stability and the processing property of vitamin C. Vitamin C was coated according to particle size(80-100 mesh, 100-140 mesh) and mixing ratio(1:1.6, 1:2.5, 1:3(w/w)) with coating solution(8% Zein-DP, 6% HPMC-FCC), and then the quality characteristics of fluidized bed micro coated vitamin C were investigated. The coating efficiency and the thickness of coating film were higher in $80{\sim}100$ mesh particle than in $100{\sim}140$ mesh particles, and coating efficiency was decreased as the coating material was increased. The distribution range of particle was more narrow in mixing ratio of 1:3(w/w) than in the other. DPPH radical scavenging activity was not affected by the particle size and the mixing ratio. There was no difference between the coating materials in terms of the quality characteristics. The optimum coating condition for fluidized bed micro-coating of vitamin C powder was selected as the particle size of $80{\sim}100$ mesh and the mixing ratio with coating solution of 1:3(w/w).

Impact of Mesh Size Difference on Zooplankton Distribution Data and Community Interpretation (망목 크기가 동물플랑크톤 분포 자료 및 군집해석에 미치는 영향)

  • Lee, Pyung-Gang;Park, Chul
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.9 no.1
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    • pp.13-19
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    • 2004
  • We compared two different zooplankton data sets simultaneously obtained at the same place with different mesh-sized nets. Smaller mesh-sized net yielded less diverse zooplankton taxa. However, it was difficult to generalize the relationship between the size of the mesh of the net used and the length of the species list observed. It was not only because the sample sizes obtained by smaller mesh net were relatively smaller due to the clogging problem but also because smaller mesh net usually collected more tiny animals that were difficult to identify at lower taxonomic categories. In terms of abundances, on the other hand, the smaller and the larger mesh-sized nets collected smaller and larger-sized animals more effectively, respectively. The abundances of small sized animals were usually greater than those of large-sized animals by about an order of differences. Due to this different catchability of the nets, the community analyses based on Principal Component Analysis led to different results for the same community.

Species composition and cluster analysis of the communities caught by dredge in relation to tooth spacing and mesh size in the coastal waters of Gangneung, Korea (강릉 연안에서 형망의 갈퀴 간격 및 망목 크기에 따른 어획 생물의 종조성 및 군집 분석)

  • An, Heui-Chun;Bae, Jae-Hyun;Park, Jong-Myung;Park, Chang-Doo;Hong, Sung-Eic
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.50 no.4
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    • pp.530-541
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    • 2014
  • The dredge gear is dragged along the bottom of the sea to catch targeted edible bottom dwelling species. Species composition and ecological index of the catches of dredge were estimated around Gangneung coastal fishing ground by dredge with different mesh size and tooth space from July to December 2013. Eight different types of dredge including four different tooth space (24.7 mm, 29.9 mm, 34.9 mm, 40.1 mm) and four different mesh size(15.5 mm, 32.7 mm, 51.1 mm, 60.0 mm) were used in the experiment. During the experiment, total catches were collected 31 species as sipunculida 1 species, mollusca 13 species, annelida 3 species, arthropoda 8 species, echinodermata 4 species and others 2 species. The dominant genus were mollusca and echinodermata while the dominant species were Megangulus venulosus, Pseudocardium sachalinensis, Schaphechinus brevis. The richness index was ranged 1.29-1.72, evenness index was 0.6-0.65 and diversity index was 1.65-1.83 according to the tooth space and mesh size of dredge. Richness index, diversity index were high at tooth space 34.9 mm dredge and ecological index showed decreasing tendency with the increasing of mesh size of dredge. Cluster and MDS analysis, based on a Bray-Curtis and similarity matrix of fourth root transformed data of number of species and wet weight, showed division into four different groups as four different tooth space (Group A), four different mesh size Group B (51.1 mm, 60.0 mm), Group C (32.7 mm) and Group D (15.5 mm).

Particle-Size Distribution Dependent upon Crushing Mechanism and Crushing Circuit (파쇄 메카니즘과 파쇄회로에 따른 입도분포)

  • Choi, Do-Young;Kim, Wan-Tae;Kim, Sang-Bae
    • Journal of the Mineralogical Society of Korea
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    • v.23 no.4
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    • pp.297-303
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    • 2010
  • We report the particle-size distribution and comminution charactersitics of dolomite depending upon crushing equipment (hammer crusher and roll crusher) and crushing circuit (open and closed). The quantity of fine particles (< 100 mesh) produced by hammer crusher was 34 wt.% which is about three times that by roll crusher. The quantity of 14~25 mesh size fraction by roll crusher was 20 wt.% higher than that produced by hammer crusher. 80 wt.% of the crushing products by hammer crushing was under 35 mesh in size, while the particles produced by roll crushing were relatively coarse. The particle size of both the hammer and roll crushers decreased by employing closed crusing circuit in comparison to open circuit. Products of required particle-size were obtained effectively depending on appropriate crushing equipment and crushing circuit.

Fishing investigation with trammel nets by mesh size in the Korean deep-water of the East Sea (삼중자망에 의한 동해 심해 수산자원의 망목별 어획특성)

  • Park, Hae-Hoon
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.49 no.1
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    • pp.1-17
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    • 2013
  • The investigation for species composition and catch in the Korean deep-water of the East Sea (also known as Sea of Japan) was carried out with trammel nets of 7 mesh sizes (6.1~24.2cm) offshore Donghae (2006) and Yangyang (2007) of Korea. The catches were 1,268kg and composed of 37 species between 200m and 1,200m in depth. The principal species caught were Taknka's snailfish, salmon snailfish, red snow crab, hunchback sculpin, snow crab, spinyhead sculpin, Tanaka's eelpout, Alaska cod and so on. Those were target fish for commercial value except salmon snailfish. The mesh sizes for the largest catch were 10.6cm and 15.2cm in the fishing ground of Donghae and Yangyang, respectively. The habitat of snow crab was shallower than that of red snow crab in both areas. Trammel net enabled to investigate fish in deep-water with small fishing vessel and rather cheap expenses in contrast to bottom trawl that required too much of it. With increasing inner mesh size of trammel net the mean size of some principal species such as Taknka's snailfish, spinyhead sculpin, hunchback sculpin, Pacific cod, snow crab, red snow crab and hybrid between snow crab and red snow crab tended to be large in certain range of mesh size.

Effect of Ground Rice Particle Size on the Brewing of Uncooked Rice Tsckju (원료백미의 분쇄정도가 무증자 당화 탁주의 발효에 미치는 영향)

  • 이순애;박희동
    • Food Science and Preservation
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    • v.2 no.2
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    • pp.269-276
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    • 1995
  • Uncooked rice Tackju was prepared from the groud rice with different particle size such as 12, 20, 35 and 50 mesh, and its characteristics were analysed during the brewing. Reducing sugar and ethanol contents as well as yeast cell counts were the highest in main mash and Tackju prepared from 20 mesh fraction. Especially, reducing sugar content was about. 1.5-2.5 times as much as that obtained from 35 or 50 mesh fraction. The final concentration of ethanol in main mash prepared from 20 mesh fraction was 14.8%(v/v). It was about 1.5%(v/v) higher than the lowest one [13.35%(v/v)] which was prepared from 12 mesh fraction. No significant difference In total acidity was observed. Sensory evaluation revealed 20 or 35 mesh Tackju to be the best in overall preference, especially in sweet and refreshing tastes.

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